This utility model relates to masseur technical field, a kind of head massager and helmet size adjustment structure thereof are provided, between the procapsid that described helmet size adjustment structure is located at the helmet of head massager and back casing, comprise tooth bar, snap close, button and extension spring, the front end of tooth bar is fixed on procapsid, the rear end of tooth bar is connected with the rear end of extension spring, the front end of described extension spring is fixed on described back casing, one end of described snap close is sticked on described tooth bar, elastic component is provided with inside the other end of described snap close, and described button this button described in end arranged outside of being provided with elastic component is for pressing this end and the one end making described snap close move inward to make described snap close engage with described tooth bar with described elastic component and described tooth bar depart from, this is by the size adjustment structure in novel, more existing adjustment structure, by the elastic reaction of elastic component, snap close and tooth bar are departed from, structure is simple, reliably, parts used are few, and more convenient operation.
